The Cromerian Stage or Cromerian Complex, also called the Cromerian (german: Cromerium), is a stage in the
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
glacial history of north-western Europe, mostly occurring more than half a million years ago. It is named after the
East Anglia
East Anglia is an area in the East of England, often defined as including the counties of Norfolk, Suffolk and Cambridgeshire. The name derives from the Anglo-Saxon kingdom of the East Angles, a people whose name originated in Anglia, in ...
n town of
Cromer
Cromer ( ) is a coastal town and civil parish on the north coast of the English county of Norfolk. It is north of Norwich, north-northeast of London and east of Sheringham on the North Sea coastline.
The local government authorities are Nor ...
in
Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...
where interglacial deposits that accumulated during part of this stage were first discovered. The
stratotype A stratotype or type section in geology is the physical location or outcrop of a particular reference exposure of a stratigraphic sequence or stratigraphic boundary. If the stratigraphic unit is layered, it is called a stratotype, whereas the stan ...
for this
interglacial
An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene in ...
is the
Cromer Forest Bed
The Cromer Forest Bed is a geological formation in Norfolk, England. It consists of river gravels, estuary and floodplain sediments predominantly clays and muds as well as sands along the coast of northern Norfolk. It is the type locality for the ...
situated at the bottom of the coastal cliff near
West Runton
West Runton is a village in North Norfolk, England, on the North Sea coast.
Toponymy
The villages name means either, Runa's farm/settlement' or 'Runi's farm/settlement'.
Overview
West Runton and East Runton together form the parish of Runton ...
. The Cromerian stage preceded the
Anglian and
Elsterian
The Elster glaciation (german: Elster-Kaltzeit, ''Elster-Glazial'' or ''Elster-Zeit'') or, less commonly, the Elsterian glaciation, in the older and popular scientific literature also called the Elster Ice Age (''Elster-Eiszeit''), is the oldest k ...
glacials and show an absence of glacial deposits in western Europe, which led to the historical terms Cromerian interglacial and the Cromerian warm period (german: Kromer-Warmzeit). It is now known that the Cromerian consisted of multiple glacial and interglacial periods.
[Böse et al. (2012), Quaternary Glaciations of Northern Europe, Quaternary Science Reviews 44, 1-25.](_blank)
/ref>
Chronology
The core of the Cromerian is the first half of the Middle Pleistocene
The Chibanian, widely known by its previous designation of Middle Pleistocene, is an age in the international geologic timescale or a stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. The ...
stage (Ionian) approximately 800-500 ka ago, just before the Anglian glaciation
The Anglian Stage is the name used in the British Isles for a middle Pleistocene glaciation. It precedes the Hoxnian Stage and follows the Cromerian Stage in the British Isles. The Anglian Stage is correlated to Marine Isotope Stage 12 (MIS 12), ...
. In terms of Marine isotope stage
Marine isotope stages (MIS), marine oxygen-isotope stages, or oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate, deduced from oxygen isotope data reflecting changes in temperature derived from data ...
s (MIS) this corresponds to MIS 19 to MIS 13. Some authors instead put the start at MIS 22, corresponding to a start 900 ka ago, which includes the last 100 ka of the Calabrian stage, after the Beestonian Stage
The Beestonian Stage is an early Pleistocene stage used in the British Isles. It is named after Beeston Cliffs near West Runton in Norfolk where deposits from this stage are preserved.
The Beestonian precedes the Cromerian Stage and follows the ...
.[Lee et al. (2011), The Glacial History of the British Isles during the early and Middle Pleistocene: Implications for the long-term development of the British Ice Sheet, Quaternary Glaciations-Extent and Chronology, pages 59-74, Elsevier.](_blank)
/ref> Some sources today correlate the Elster glaciation
The Elster glaciation (german: Elster-Kaltzeit, ''Elster-Glazial'' or ''Elster-Zeit'') or, less commonly, the Elsterian glaciation, in the older and popular scientific literature also called the Elster Ice Age (''Elster-Eiszeit''), is the oldest k ...
to MIS 10 instead of MIS 12, while keeping the Cromerian running up to the start of the Elsterian. The result is an end to the Cromerian stage in continental Europe at the end of MIS 11 (400 ka ago), and that the continental Cromerian continues beyond its end in Britain and Ireland and runs in parallel to the Anglian and Hoxnian Stage
__NOTOC__
The Hoxnian Stage was a middle Pleistocene stage (Pleistocene from million to 11,700 years BP) of the geological history of the British Isles. It was an interglacial which preceded the Wolstonian Stage and followed the Anglian Stage. I ...
s (MIS 12-11).
In the Alpine region
The main valleys of the Alps, orographically by drainage basin.
Rhine basin (North Sea)
High Rhine
*Aare
** Limmat
***Linth (Glarus)
****Lake Walen
*****Seeztal
**** Klöntal
****Sernftal
** Reuss
***Lake Lucerne
****Sarner Aa (Brünig Pass co ...
the corresponding stage is called Günz
The Günz is a river in Bavaria, Germany.
It is formed near Lauben by the confluence of its two source rivers: the Östliche Günz (eastern Günz) and the Westliche Günz (western Günz). It is approx. long (including its western source river) ...
.
The Cromerian had been equated to the Aftonian in North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
. However, the Aftonian, along with the Yarmouthian (Yarmouth), Kansan, and Nebraskan, have been abandoned by North American Quaternary geologists and merged into the Pre-Illinoian
The Pre-Illinoian Stage is used by Quaternary geologists for the early and middle Pleistocene glacial and interglacial periods of geologic time in North America from ~2.5–0.2 Ma (million years ago).
North America
As the oldest stage in t ...
.[Hallberg, G.R., 1986, ''Pre-Wisconsin glacial stratigraphy of the Central Plains region in Iowa, Nebraska, Kansas, and Missouri'', Quaternary Science Reviews. vol. 5, pp. 11-15.][Richmond, G.M. and D.S. Fullerton, 1986, ''Summation of Quaternary glaciations in the United States of America'', Quaternary Science Reviews. vol. 5, pp. 183-196.] At this time, the Cromerian is correlated with the period of time, which includes the Pre-Illinoian C, Pre-Illinoian D, and Pre-Illinoian E glaciations of North America.[Walker, M., 2005, ''Quaternary Dating Methods'', John Wiley & Son, Chichester, United Kingdom. ]
Proposals for structuring the Cromerian complex have become quite confusing. Great potential for a full breakdown has been provided by the extensive, continental series at Gorleben
Gorleben is a small municipality ('' Gemeinde'') in the Gartow region of the Lüchow-Dannenberg district in the far north-east of Lower Saxony, Germany, a region also known as the Wendland.
Gorleben was first recorded as a town by the rulers of ...
.
Glacial cycles
Based on a lack of glacial evidence in Western Europe for the Middle Pleistocene
The Chibanian, widely known by its previous designation of Middle Pleistocene, is an age in the international geologic timescale or a stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. The ...
(Ionian) before the Anglian glaciation
The Anglian Stage is the name used in the British Isles for a middle Pleistocene glaciation. It precedes the Hoxnian Stage and follows the Cromerian Stage in the British Isles. The Anglian Stage is correlated to Marine Isotope Stage 12 (MIS 12), ...
, the Cromerian was originally thought to be a period without major glaciations. However, there is evidence for ice-rafting of material across the North Sea from this period. Investigations in the 1950s of oxygene isotopes in deep sea core samples revealed five glacial cycles during MIS 22 - MIS 13. The Mid-Pleistocene Transition
The Mid-Pleistocene Transition (MPT), also known as the Mid-Pleistocene Revolution (MPR), is a fundamental change in the behaviour of glacial cycles during the Quaternary glaciations. The transition happened approximately 1.25–0.7 milli ...
to the 100,000 year glacial cycle became established during the Cromerian. Four of the glaciations (MIS 22, MIS 20, MIS 18, MIS 14) were moderate, probably involving low-land glaciation in Scandinavia, but not spreading to England and northern Germany. One of the glaciations, Marine Isotope Stage 16 (MIS 16), is globally as strong as the most recent glaciations, MIS 6 (main Saale
The Saale (), also known as the Saxon Saale (german: Sächsische Saale) and Thuringian Saale (german: Thüringische Saale), is a river in Germany and a left-bank tributary of the Elbe. It is not to be confused with the smaller Fränkische Saale, ...
) and MIS 2 ( Weichsel/Devensian). There is plenty of evidence in Russia for a major glaciation during this stage, which is called the Don Glaciation
The Don Glaciation, also known as the Donian Glaciation and the Donian Stage, was the major glaciation of the East European Plain, 0.5–0.8 million years ago, during the Cromerian Stage of the Middle Pleistocene. It is correlated to Marine Isotop ...
and believed to correspond to MIS 16. It is not clear why western Europe seems so unaffected by this major glacial.
Fossils
In 1990 the West Runton Mammoth
The West Runton Mammoth is a fossilized skeleton of a steppe mammoth (''Mammuthus trogontherii'') found in the West Runton Cliffs, cliffs of West Runton in the county of Norfolk, England in 1990. The find is the largest nearly complete mammoth ske ...
skeleton was found, the best example of the species Mammuthus trogontherii
The steppe mammoth (''Mammuthus trogontherii'', sometimes ''Mammuthus armeniacus'') is an extinct species of Elephantidae that ranged over most of northern Eurasia during the late Early and Middle Pleistocene, approximately 1.8 million-200,000 y ...
to be unearthed so far.
A significant fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
site, with animal remains dating about 600,000 years ago, is the Mosbach Sands, named after an abandoned village near Wiesbaden
Wiesbaden () is a city in central western Germany and the capital of the state of Hesse. , it had 290,955 inhabitants, plus approximately 21,000 United States citizens (mostly associated with the United States Army). The Wiesbaden urban area ...
, Germany.[Ernst Probst: ''Deutschland in der Urzeit''. Munich: Bertelsmann, 1986]
German National Library catalogue
/ref>
See also
* Timeline of glaciation
There have been five or six major ice ages in the history of Earth over the past 3 billion years.
The Late Cenozoic Ice Age began 34 million years ago, its latest phase being the Quaternary glaciation, in progress since 2.58 million years ago. ...
* Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
* Cromer Forest Bed
The Cromer Forest Bed is a geological formation in Norfolk, England. It consists of river gravels, estuary and floodplain sediments predominantly clays and muds as well as sands along the coast of northern Norfolk. It is the type locality for the ...
References
Sources
www.Stratigraphy.org
{{North German glaciations
Quaternary geochronology
Ice ages
Pleistocene
Interglacials